Vishwanatha-HD commented on code in PR #48180:
URL: https://github.com/apache/arrow/pull/48180#discussion_r2599504808
##########
cpp/src/arrow/compute/util.cc:
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@@ -118,7 +124,22 @@ void bits_to_indexes_internal(int64_t hardware_flags,
const int num_bits,
// Optionally process the last partial word with masking out bits outside
range
if (tail) {
const uint8_t* bits_tail = bits + (num_bits - tail) / 8;
+#if ARROW_LITTLE_ENDIAN
uint64_t word = SafeLoadUpTo8Bytes(bits_tail, (tail + 7) / 8);
+#else
+ int tail_bytes = (tail + 7) / 8;
+ uint64_t word;
+ if (tail_bytes == 8) {
+ word = util::SafeLoad(reinterpret_cast<const uint64_t*>(bits_tail));
+ } else {
+ // For bit manipulation, always load into least significant bits
+ // to ensure compatibility with CountTrailingZeros on Big-endian systems
+ word = 0;
+ for (int i = 0; i < tail_bytes; ++i) {
+ word |= static_cast<uint64_t>(bits_tail[i]) << (8 * i);
+ }
+ }
+#endif
Review Comment:
Hi @zanmato1984..
I made the code changes as per your suggestion above.. but unfortunately,
the testcase doesnt pass.. The thing is that its not just the "byteswap" that
is required on the BE systems..
./debug/arrow-compute-row-test
--gtest_filter=KeyCompare.CompareColumnsToRowsCuriousFSB
Note: Google Test filter = KeyCompare.CompareColumnsToRowsCuriousFSB
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from KeyCompare
[ RUN ] KeyCompare.CompareColumnsToRowsCuriousFSB
arrow/cpp/src/arrow/compute/row/compare_test.cc:103: Failure
Expected equality of these values:
num_rows_no_match
Which is: 7
1
[ FAILED ] KeyCompare.CompareColumnsToRowsCuriousFSB (2 ms)
[----------] 1 test from KeyCompare (2 ms total)
[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (18 ms total)
[ PASSED ] 0 tests.
[ FAILED ] 1 test, listed below:
[ FAILED ] KeyCompare.CompareColumnsToRowsCuriousFSB
1 FAILED TEST
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